ReferentialIntegrityException when adding a field, remodel, and edit an updated document

I've added an html field to an existing document type using the document type editor.
After saving and hitting Update content, the field had appeared in an existing document, which was expected.
However, after editing the document, saving it lead to this error:

10.07.2008 11:41:52 ERROR [org.hippoecm.frontend.plugin.workflow.AbstractWorkflo
wPlugin$2.onClick():155] Invalid data to save
javax.jcr.ReferentialIntegrityException: 4017a104-db71-4b0f-9c14-68c915413b86: t
he node cannot be removed because it is still being referenced.
at org.apache.jackrabbit.core.state.SharedItemStateManager.checkReferent
ialIntegrity(SharedItemStateManager.java:1406)
at org.apache.jackrabbit.core.state.SharedItemStateManager$Update.begin(
SharedItemStateManager.java:556)
at org.apache.jackrabbit.core.state.SharedItemStateManager.beginUpdate(S
haredItemStateManager.java:827)
at org.apache.jackrabbit.core.state.SharedItemStateManager.update(Shared
ItemStateManager.java:857)
at org.apache.jackrabbit.core.state.LocalItemStateManager.update(LocalIt
emStateManager.java:324)
at org.apache.jackrabbit.core.state.XAItemStateManager.update(XAItemStat
eManager.java:313)
at org.hippoecm.repository.jackrabbit.HippoLocalItemStateManager.update(
HippoLocalItemStateManager.java:175)
at org.apache.jackrabbit.core.state.LocalItemStateManager.update(LocalIt
emStateManager.java:300)
at org.hippoecm.repository.jackrabbit.HippoLocalItemStateManager.update(
HippoLocalItemStateManager.java:182)
at org.apache.jackrabbit.core.state.SessionItemStateManager.update(Sessi
onItemStateManager.java:306)
at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:1244)
at org.apache.jackrabbit.core.SessionImpl.save(SessionImpl.java:896)
at org.hippoecm.repository.decorating.SessionDecorator.save(SessionDecor
ator.java:268)
at org.hippoecm.repository.decorating.WorkflowManagerImpl$WorkflowInvoca
tionHandler.invoke(WorkflowManagerImpl.java:439)
at $Proxy7.commitEditableInstance(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:294)
at sun.rmi.transport.Transport$1.run(Transport.java:153)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:149)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:4
66)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport
.java:707)
at java.lang.Thread.run(Thread.java:595)
at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Stream
RemoteCall.java:247)
at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:
223)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:126)
at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Remo
teObjectInvocationHandler.java:179)
at java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvo
cationHandler.java:132)
at $Proxy7.commitEditableInstance(Unknown Source)
at org.hippoecm.frontend.plugins.reviewedactions.EditingReviewedActionsW
orkflowPlugin$1.execute(EditingReviewedActionsWorkflowPlugin.java:44)
at org.hippoecm.frontend.plugin.workflow.AbstractWorkflowPlugin$2.onClic
k(AbstractWorkflowPlugin.java:145)
at org.apache.wicket.ajax.markup.html.AjaxLink$1.onEvent(AjaxLink.java:6
5)
at org.apache.wicket.ajax.AjaxEventBehavior.respond(AjaxEventBehavior.ja
va:163)
at org.apache.wicket.ajax.AbstractDefaultAjaxBehavior.onRequest(Abstract
DefaultAjaxBehavior.java:293)
at org.apache.wicket.request.target.component.listener.BehaviorRequestTa
rget.processEvents(BehaviorRequestTarget.java:100)
at org.apache.wicket.request.AbstractRequestCycleProcessor.processEvents
(AbstractRequestCycleProcessor.java:91)
at org.apache.wicket.RequestCycle.processEventsAndRespond(RequestCycle.j
ava:1171)
at org.apache.wicket.RequestCycle.step(RequestCycle.java:1248)
at org.apache.wicket.RequestCycle.steps(RequestCycle.java:1349)
at org.apache.wicket.RequestCycle.request(RequestCycle.java:493)
at org.apache.wicket.protocol.http.WicketFilter.doGet(WicketFilter.java:
387)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.ja
va:199)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(Servlet
Handler.java:1084)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:3
60)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.jav
a:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:1
81)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:7
26)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)

at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHand
lerCollection.java:206)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.
java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:1
52)
at org.mortbay.jetty.Server.handle(Server.java:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:50
5)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpCo
nnection.java:829)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:514)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.ja
va:395)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.j
ava:488)